Electric oil pump

ABSTRACT

An electric oil pump includes a motor part having a shaft, a pump part located on a front side of the motor part and driven via the shaft, and a control part which controls the motor part. The motor part includes a rotor, a stator, and a motor housing having a cylindrical portion which accommodates the rotor and the stator. The pump part includes a pump rotor, and a pump housing which accommodates the pump rotor. The control part includes a substrate having a surface on which a plurality of electronic components are mounted. The surface of the substrate is disposed to face the cylindrical portion and extends in the axial direction. A coil, which is provided on the stator, and the substrate are electrically connected via a connecting bus bar assembly. The connecting bus bar assembly is disposed between the cylindrical portion and the substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Japan Application No. 2018-068598, filed on Mar. 30, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND Technical Field

The disclosure relates to an electric oil pump.

Description of Related Art

An electric oil pump having a structure including a pump part, a motor part for driving the pump part, and a control part for controlling an operation of the motor part is known. In this electric oil pump, for example, the pump part is disposed on one side of the motor part in the axial direction, and a shaft extending from the motor part passes through a pump body of the pump part. An accommodating portion which is open on one side of the pump body in the axial direction and recessed toward the other side in the axial direction is provided in an end surface of the pump body on one side in the axial direction. A pump rotor is accommodated in the accommodating portion. Further, the control part has a substrate on which electronic components for driving the motor part are mounted.

Patent Document 1 (Japanese Patent Laid-Open No. 2012-29793) describes a structure of an electronic blood pressure monitor including a pump which introduces air into a cuff attached to a measurement part of a person to be measured, a pump motor which drives the pump, and a substrate which controls the electronic blood pressure monitor. The substrate is disposed above the motor part of the pump motor, and a surface of the substrate on which the electronic components are mounted is disposed along a central axis of the shaft of the pump motor in the axial direction.

An internal space of a housing of the electronic blood pressure monitor described in Patent Document 1 is wider than a size of the pump. Also, the other side of the substrate in the axial direction which is disposed above the pump part is disposed above the pump part in a state in which it protrudes from the other end of the pump part in the axial direction. Therefore, in the pump of the electronic blood pressure monitor described in Patent Document 1, the demand for miniaturization is lower than that of the electric oil pump.

On the other hand, for example, in an electric oil pump applied to a vehicle, the demand for miniaturization is high so as to ensure a minimum ground clearance of the vehicle. Therefore, when the pump and the substrate in the electronic blood pressure monitor described in Patent Document 1 are applied to the electric oil pump, a size of the electric oil pump may be increased.

SUMMARY

According to an exemplary embodiment of the disclosure, there is provided an electric oil pump including a motor part having a shaft disposed along a central axis extending in an axial direction, a pump part located on one side of the motor part in the axial direction and driven by the motor part via the shaft to discharge oil, and a control part which controls an operation of the motor part, wherein the motor part includes a rotor fixed to the other side of the shaft in the axial direction, a stator disposed to face the rotor, and a motor housing having a cylindrical portion which accommodates the rotor and the stator, the pump part includes a pump rotor mounted on the shaft which protrudes from the motor part to one side in the axial direction and a pump housing having an accommodating portion which accommodates the pump rotor, the control part includes a plurality of electronic components and a substrate having a surface on which the plurality of electronic components are mounted, the surface of the substrate is disposed radially outward from the cylindrical portion of the motor housing to face the motor housing and extends in the axial direction, the stator has a coil, the coil and the substrate are electrically connected via a connecting bus bar assembly, and the connecting bus bar assembly is disposed between the cylindrical portion of the motor part and the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an electric oil pump according to a first embodiment.

FIG. 2 is a perspective view of a motor housing.

FIG. 3 is a front view of a connecting bus bar assembly.

FIG. 4 is an internal structural view of the electric oil pump in which illustration of the motor housing is omitted.

FIG. 5 is a side view of the connecting bus bar assembly.

DESCRIPTION OF THE EMBODIMENTS

The disclosure provides an electric oil pump having a substrate and capable of being downsized in an axial direction.

According to the exemplary embodiment of the disclosure, it is possible to provide an electric oil pump having a substrate and capable of being downsized in an axial direction.

Hereinafter, an electric oil pump according to an embodiment of the disclosure will be described with reference to the drawings. In the embodiment, an electric oil pump which supplies oil to a transmission mounted in a vehicle such as an automobile will be described. Further, in the following drawings, to make each configuration easy to understand, the actual structure and the scale and number in each structure may be different from each other.

Further, in the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, a Z axis direction is a direction (a right and left direction in FIG. 1) parallel to an axial direction of a central axis J shown in FIG. 1. An X axis direction is a direction parallel to a short side direction of the electric oil pump shown in FIG. 1, that is, a direction orthogonal to the paper surface of FIG. 1. A Y axis direction is a direction orthogonal to both the X axis direction and the Z axis direction.

Further, in the following description, a positive side (+Z side) in the Z axis direction is referred to as a “rear side,” and a negative side in the Z axis direction (−Z side) is referred to as a “front side.” The rear side and the front side are simply used for explanation and do not limit an actual positional relationship and direction. Also, unless otherwise noted, the direction (the Z axis direction) parallel to the central axis J is simply referred to as an “axial direction,” a radial direction around the central axis J is simply referred to as a “radial direction,” and a circumferential direction around the central axis J, that is, an axial circumference (a θ direction) of the central axis J, is simply referred to as a “circumferential direction.”

In the specification, the term “extending in the axial direction” includes not only a case of strictly extending in the axial direction (the Z axis direction) but also a case of extending in a direction inclined in a range of less than 45° with respect to the axial direction. Also, in the specification, the term “extending in the radial direction” includes not only a case of strictly extending in the radial direction, that is, in a direction perpendicular to the axial direction (the Z axis direction), but also a case of extending in a direction inclined in a range of less than 45° with respect to the radial direction.

First Embodiment <Entire Configuration>

FIG. 1 is a cross-sectional view of an electric oil pump according to a first embodiment. FIG. 2 is a perspective view of a motor housing. As shown in FIG. 1, the electric oil pump 1 of the embodiment includes a motor part 10, a pump part 40, and a control part 82. The motor part 10 has a shaft 11 disposed along the central axis J extending in the axial direction. The pump part 40 is located on one side (the front side) of the motor part 10 in the axial direction, is driven by the motor part 10 via the shaft 11, and discharges oil. The control part 82 is disposed on the +Y side of the motor part 10 and controls an operation of the motor part 10. Hereinafter, each element will be described in detail.

<Motor Part 10>

As shown in FIG. 1, the motor part 10 includes a rotor 20, a stator 22, and a motor housing 13.

The motor part 10 is, for example, an inner rotor type motor. The rotor 20 is fixed to an outer circumferential surface of the shaft 11, and the stator 22 is disposed radially outward from the rotor 20. In the embodiment, the rotor 20 is fixed to the other side (the rear side) of the shaft 11 in the axial direction. The stator 22 is disposed to face the rotor 20.

(Motor Housing 13)

As shown in FIG. 2, the motor housing 13 includes a cylindrical portion 13 d which has a cylindrical shape and accommodates the stator 22, and a case 50 which extends from an outer surface of the cylindrical portion 13 d in a direction (the Y axis direction) orthogonal to the axial direction. The cylindrical portion 13 d accommodates the rotor 20 and the stator 22. The motor housing 13 has a stator holding portion 13 a which holds the stator 22. The motor housing 13 is formed of a metal. The cylindrical portion 13 d and the case 50 are integrally molded. Therefore, the cylindrical portion 13 d and the case 50 are a single member. A motor cover 72 c is disposed at an end of the cylindrical portion 13 d on the other side (the rear side) in the axial direction, and a rear side opening of the cylindrical portion 13 d is closed by the motor cover 72 c. Further, the motor housing 13 has a bus bar assembly 30 which is connected to a coil 22 b extending from the stator 22.

(Stator Holding Portion 13 a)

The stator holding portion 13 a has a cylindrical shape which extends in the axial direction. The shaft 11 of the motor part 10, the rotor 20, and the stator 22 are disposed in the stator holding portion 13 a. An outer surface of the stator 22, that is, an outer surface of a core back portion 22 a, which will be described later, is fitted to an inner surface 13 a 1 of the stator holding portion 13 a. Accordingly, the stator 22 is accommodated in the stator holding portion 13 a.

(Bus Bar Assembly 30)

As shown in FIG. 1, the bus bar assembly 30 is connected to a coil end 22 e of the coil 22 b extending from the stator 22. A connecting bus bar 35 of the bus bar assembly 30 is connected to a connecting bus bar assembly 75 connected to a substrate 82 a. Therefore, the coil end 22 e is electrically connected to the substrate 82 a via the connecting bus bar assembly 75.

The bus bar assembly 30 includes a plurality of connecting bus bars 35, which have a tubular shape and are connected to the coil ends 22 e, and an assembly main body portion 33, in which the connecting bus bars 35 are disposed. In the embodiment, the connecting bus bar 35 is formed of a metal and is integrated with the assembly main body portion 33 by insert molding.

The coil end 22 e protrudes from an end of the motor part 10 on the other side (the rear side) in the axial direction. Assuming that two coil ends 22 e which are adjacent to each other in the circumferential direction are one coil end group 22 f (refer to FIG. 4), three coil end groups 22 f are disposed at regular intervals in the circumferential direction. Therefore, the bus bar assembly 30 has three connecting bus bars 35 connected to the three coil end groups 22 f, respectively.

(Assembly Main Body Portion 33)

As shown in FIG. 1, the assembly main body portion 33 has a tubular portion 33 b which has a tubular shape and extends in a cylindrical shape. The tubular portion 33 b is open on one side (the front side) in the axial direction and has a bottom portion 33 a on the rear side. An insertion hole 33 c through which the shaft 11 passes is provided at a center portion of the bottom portion 33 a. An inner diameter of the insertion hole 33 c is larger than an outer diameter of the shaft 11. Therefore, the insertion hole 33 c is capable of suppressing shaking of the rear side of the shaft 11. The bus bar assembly 30 is fixed to the inner surface 13 a 1 of the cylindrical portion 13 d of the motor housing 13. In the present embodiment, the bus bar assembly 30 is fixed to the inner surface 13 a 1 of the motor housing 13 by press fitting.

(Connecting Bus Bar Assembly 75)

FIG. 3 is a front view of the connecting bus bar assembly. FIG. 4 is an internal structural view of the electric oil pump in which illustration of the motor housing is omitted. As shown in FIGS. 3 and 4, the connecting bus bar assembly 75 includes a connecting assembly main body portion 75 a which extends along a radially outer side of the shaft 11 in a direction orthogonal to the central axis J of the shaft, and a connecting bus bar 73 disposed in the connecting assembly main body portion 75 a. In the embodiment, three connecting bus bars 73 are disposed in the connecting assembly main body portion 75 a. The connecting bus bars 73 are formed of a metal, and the connecting bus bars 73 and the connecting assembly main body portion 75 a are an integrally molded product formed of a resin.

Each of the connecting bus bars 73 includes a connecting assembly main body portion 73 a, a motor-side terminal portion 73 b provided at one end side of the connecting bus bar main body portion 73 a and connected to the connecting bus bar 35, and a substrate-side terminal portion 73 c provided on the other end side of the connecting bus bar main body portion 73 a and connected to the substrate 82 a. The connecting bus bar main body portion 73 a and the motor-side terminal portion 73 b extend linearly. The other end side of the connecting bus bar main body portion 73 a has a bent portion 73 d which is bent toward the rear side. The bent portion 73 d has a substrate-side connecting portion 35 c of which an end on the rear side linearly extends outward in the radial direction. The substrate-side connecting portion 35 c is electrically connected through a through hole portion 82 f provided in the substrate 82 a.

(Rotor 20)

As shown in FIG. 1, the rotor 20 is fixed to the rear side of the shaft 11 with respect to the pump part 40. The rotor 20 has a rotor core 20 a and a rotor magnet 20 b. The rotor core 20 a surrounds the shaft 11 around the axis (in the θ direction) and is fixed to the shaft 11. The rotor magnet 20 b is fixed to an outer surface of the rotor core 20 a around the axis (in the θ direction). The rotor core 20 a and the rotor magnet 20 b rotate together with the shaft 11. Incidentally, the rotor 20 may be an embedded magnet type in which a permanent magnet is embedded in the rotor 20. The embedded magnet type rotor 20 can reduce a possibility that the magnet is separated by a centrifugal force and can positively use a reluctance torque as compared with a surface magnet type in which the permanent magnet is provided on the surface of the rotor 20.

(Stator 22)

The stator 22 is disposed radially outward from the rotor 20 to face the rotor 20, surrounds the rotor 20 around the axis (in the θ direction) and rotates the rotor 20 around the central axis J. The stator 22 has a core back portion 22 a, a tooth portion 22 c, a coil 22 b, and an insulator (a bobbin) 22 d.

The core back portion 22 a has a cylindrical shape which is concentric with the shaft 11. The tooth portion 22 c extends from an inner surface of the core back portion 22 a toward the shaft 11. A plurality of the tooth portions 22 c are provided and disposed at regular intervals in the circumferential direction of the inner surface of the core back portion 22 a. The coil 22 b is wound around the insulator 22 d. The insulator 22 d is mounted at each of the tooth portions 22 c.

(Shaft 11)

As shown in FIG. 1, the shaft 11 extends around the central axis J extending in the axial direction and passes through the motor part 10. The front side (the −Z side) of the shaft 11 protrudes from the motor part 10 and extends into the pump part 40. The front side of the shaft 11 is fixed to an inner rotor 47 a of the pump part 40. The front side of the shaft 11 passes through and is supported by a bearing through hole 50 a provided on the front side of the case 50 of the motor housing 13. That is, the bearing through hole 50 a serves as a sliding bearing which rotatably supports the shaft 11. Details of the bearing through hole 50 a will be described later.

The rear side of the shaft 11 passes through the insertion hole 33 c of the bus bar assembly 30, but the insertion hole 33 c does not serve as a bearing. Therefore, the rotor 20 rotates in a cantilever supported state in which only the front side thereof is supported.

<Control Part 82>

As shown in FIGS. 3 and 4, the control part 82 includes a plurality of electronic components 82 b and the substrate 82 a having a surface 82 c on which the plurality of electronic components 82 b are mounted. The control part 82 generates a signal for driving the motor part 10 and outputs the signal to the motor part 10. The substrate 82 a is accommodated in the case 50 and is supported by and fixed to the connecting bus bar assembly 75 extending radially outward from the cylindrical portion 13 d of the motor housing 13.

<Pump Part 40>

As shown in FIG. 1, the pump part 40 is located on one side (the front side) of the motor part 10 in the axial direction. The pump part 40 is driven by the motor part 10 via the shaft 11. The pump part 40 includes a pump rotor 47 and a pump housing 51. In the embodiment, the pump housing 51 includes a pump body 52 and a pump cover 57. The pump housing 51 has an accommodating portion 60 which accommodates the pump rotor 47 between the pump body 52 and the pump cover 57. Each part will be described in detail below.

(Pump Body 52)

As shown in FIG. 1, the pump body 52 is disposed at a front side end of the motor housing 13. The pump body 52 is integrally molded with the case 50. Therefore, the pump body 52 and the case 50 are the same member. The pump body 52 has a concave portion 54 which is recessed from an end surface 52 c thereof on the rear side (the +Z side) toward the front side (the −Z side). A seal member 59 is accommodated in the concave portion 54. The seal member 59 seals oil leaking from the pump rotor 47. The pump body 52 is the same member as the motor housing 13.

The pump body 52 has the bearing through hole 50 a passing therethrough along the central axis J. In the bearing through hole 50 a, both ends thereof in the axial direction are open, the shaft 11 passes therethrough, an opening thereof on the rear side (the +Z side) is open in the concave portion 54, and an opening thereof on the front side (the −Z side) is open in a front end surface 52 d of the pump body 52. This bearing through hole 50 a is a sliding bearing which rotatably supports the shaft 11.

(Pump Rotor 47)

As shown in FIG. 1, the pump rotor 47 is mounted on the front side of the shaft 11. The pump rotor 47 includes an inner rotor 47 a, an outer rotor 47 b, and a rotor body 47 c. The pump rotor 47 is mounted on the shaft 11. More specifically, the pump rotor 47 is mounted on the front side (the −Z side) of the shaft 11. The inner rotor 47 a is fixed to the shaft 11. The outer rotor 47 b surrounds the outer side of the inner rotor 47 a in the radial direction. The rotor body 47 c surrounds the outer side of the outer rotor 47 b in the radial direction. The rotor body 47 c is fixed to the pump body 52.

The inner rotor 47 a has an annular shape. The inner rotor 47 a is a gear having teeth on a radially outer side surface thereof. The inner rotor 47 a rotates around the axis (in the θ direction) together with the shaft 11. The outer rotor 47 b has an annular shape which surrounds a radially outer side of the inner rotor 47 a. The outer rotor 47 b is a gear having teeth on a radially inner surface thereof. A radially outer side surface of the outer rotor 47 b has a circular shape. A radially inner side surface of the rotor body 47 c has a circular shape.

The gear on the radially outer side surface of the inner rotor 47 a and the gear on the radially inner side surface of the outer rotor 47 b engage with each other, and the inner rotor 47 a is rotated by the shaft 11, and thus the outer rotor 47 b rotates. That is, the pump rotor 47 is rotated by the rotation of the shaft 11. In other words, the motor part 10 and the pump part 40 have the same rotation axis. Accordingly, it is possible to suppress a size of the electric oil pump 1 from increasing in the axial direction.

Also, as the inner rotor 47 a and the outer rotor 47 b rotate, a volume between engagement portions of the inner rotor 47 a and the outer rotor 47 b changes. A region in which the volume decreases becomes a pressurization region, and a region in which the volume increases is a negative pressure region. A suction port (not shown) of the pump cover 57 is disposed on the front side of the negative pressure region of the pump rotor 47. Further, a discharge port (not shown) of the pump cover 57 is disposed on the front side of the pressurization region of the pump rotor 47.

(Pump Cover 57)

As shown in FIG. 1, the pump cover 57 is mounted on the front side of the pump rotor 47. The pump cover 57 is fixed to the rotor body 47 c of the pump rotor 47. The pump cover 57 is mounted on and fixed to the pump body 52 together with the rotor body 47 c of the pump rotor 47. The pump cover 57 has an inlet connected to the suction port. The pump cover 57 has an outlet connected to the discharge port.

Oil suctioned into the pump rotor 47 from the inlet provided in the pump cover 57 via the suction port of the pump cover 57 is accommodated in a volume portion between the inner rotor 47 a and the outer rotor 47 b and is delivered to the pressurization region. Thereafter, the oil is discharged from the outlet provided in the pump cover 57 via the discharge port of the pump cover 57. A suction direction in the inlet and a discharge direction in the outlet are orthogonal to each other. Accordingly, it is possible to reduce a pressure loss from the inlet to the outlet and to make a flow of the oil smooth.

As shown in FIG. 2, the inlet is disposed on the side in which the substrate 82 a is disposed with respect to the motor part 10. Thus, it is possible to reduce a size of the electric oil pump 1 in the radial direction by overlapping an arrangement space of the inlet with an arrangement space of the substrate 82 a and minimizing the arrangement space which is separately required.

(Case 50)

As shown in FIGS. 1 and 2, the motor housing 13 includes the cylindrical portion 13 d and the case 50. The motor housing 13 is formed in a rectangular parallelepiped shape and has the cylindrical portion 13 d extending in the axial direction thereof. The cylindrical portion 13 d has the end surface 52 c in which the rear side thereof is open and the front side thereof is closed. Therefore, the cylindrical portion 13 d is a cylinder having a bottom. The bearing through hole 50 a which passes therethrough in the axial direction and through which the shaft 11 passes is provided in the end surface 52 c.

The case 50 is a portion of the motor housing 13 outside the cylindrical portion 13 d. The case 50 has a substrate accommodating portion 84 which is located radially outward from the cylindrical portion 13 d, extends in the axial direction, and accommodates the substrate 82 a. Further, the substrate accommodating portion 84 has a placing surface portion 84 a which is disposed within an axial range of an assembly 45 to face the cylindrical portion 13 d and on which the substrate 82 a is placed. The assembly 45 refers to a combination of the motor part 10 and the pump part 40. In the embodiment, the substrate accommodating portion 84 is located on the +Y side from the cylindrical portion 13 d, and the placing surface portion 84 a is disposed to face the cylindrical portion 13 d. The placing surface portion 84 a extends in the axial direction and the X axis direction. That is, the placing surface portion 84 a extends in a direction orthogonal to the Y axis direction. Therefore, it is possible to suppress an increase in the size of the electric oil pump 1 in the Y axis direction.

The substrate accommodating portion 84 is in the form of a bottomed container which is recessed toward the cylindrical portion 13 d and includes the placing surface portion 84 a which extends in a planar shape in the axial direction and an annular protruding portion 84 b which protrudes toward the +Y side from a circumferential edge portion of the placing surface portion 84 a. The placing surface portion 84 a has a rectangular shape as seen in a direction of the −Y side. The substrate 82 a is accommodated in the substrate accommodating portion 84.

(Substrate 82 a)

In the substrate 82 a, as shown in FIGS. 1 and 4, a surface 82 c of the substrate 82 a is disposed on a radially outer side of the cylindrical portion 13 d of the motor housing 13 to face the cylindrical portion 13 d of the motor housing 13 and extends in the axial direction. Further, the substrate 82 a has an axial length shorter than an axial length of the assembly 45 formed by combining the motor part 10 and the pump part 40 and is disposed within an axial range of the assembly 45. In the embodiment, the substrate 82 a is formed in a rectangular shape and has a similar shape smaller than the placing surface portion 84 a of the substrate accommodating portion 84. In the substrate 82 a, the surface 82 c of the substrate 82 a is disposed along the placing surface portion 84 a of the substrate accommodating portion 84. Therefore, the surface 82 c of the substrate 82 a is disposed to face the cylindrical portion 13 d of the motor housing 13. Also, in the substrate 82 a, a front side end of the substrate 82 a is located on the front side of the assembly 45, and a rear side end of the substrate 82 a is located on the rear side of the assembly 45. Therefore, the axial length of the substrate 82 a is shorter than the axial length of the assembly 45, and the substrate 82 a is disposed within the axial range of the assembly 45. Accordingly, a length of the electric oil pump 1 in the axial direction is suppressed, and the size thereof can be reduced.

The substrate 82 a has the surface 82 c on which the plurality of electronic components 82 b are mounted. In the embodiment, the substrate 82 a is formed in a plate shape and has planar surfaces 82 c on both sides thereof in the Y axis direction. The electronic components 82 b are mounted on these surfaces 82 c. The plurality of electronic components 82 b mounted on the substrate 82 a are disposed on the substrate 82 a to face the cylindrical portion 13 d of the motor housing 13. In the embodiment, the electronic components 82 b are disposed in the Y axis direction. Also, among the plurality of electronic components 82 b, an electronic component 82 b 1 having a relatively high height is mounted on a front side surface 82 c 2 of the surfaces 82 c of the substrate 82 a opposite to a rear side surface 82 c 1 facing the motor part 10. In the embodiment, the electronic component 82 b 1 having a relatively high height is a capacitor. The electronic component 82 b 1 having a relatively high height may be a choke coil. Therefore, it is possible to increase a distance between the motor part 10 and the electronic component 82 b 1 having a relatively high height. Thus, adverse influence on the electronic component 82 b 1 due to heat generation from the motor part 10 can be suppressed.

A connector portion 82 d electrically connected to the substrate 82 a is provided on one side (the front side) of the substrate 82 a in the axial direction. On the other hand, the connecting bus bar 73 of the connecting bus bar assembly 75 is electrically connected to the other side (the rear side) of the substrate 82 a in the axial direction. In the embodiment, the connector portion 82 d is a connection terminal. The connector portion 82 d extends from the front side surface 82 c 2 of the front side end of the substrate 82 a in the Y axis direction. A plurality of the connector portions 82 d are disposed at intervals in the X axis direction. That is, the connector portions 82 d have a plurality of connection terminals. Therefore, the connector portions 82 d may be disposed at positions away from a connection point in which the connecting bus bar 73 is connected to the substrate 82 a. Therefore, it is possible to suppress the possibility that noise generated from the connecting bus bar 73 may adversely affect the connector portions 82 d.

As shown in FIGS. 1 and 2, the case 50 has a hole portion 50 b which extends between the other side (the rear side) of the cylindrical portion 13 d in the axial direction and the substrate 82 a. In the embodiment, the hole portion 50 b is open to the rear side of the substrate accommodating portion 84, extends toward the cylindrical portion 13 d inside the case 50 and is open to the cylindrical portion 13 d. A cross section of the hole portion 50 b is slightly larger than a cross section of the connecting bus bar assembly 75 and has a similar shape. Therefore, the connecting bus bar assembly 75 can be positioned in the hole portion 50 b by causing the connecting bus bar assembly 75 to pass through the hole portion 50 b.

As shown in FIG. 4, the substrate-side terminal portion 73 c of the connecting bus bar 73 is connected to the end of the substrate 82 a on the other side (the front side) in the axial direction. Also, a circuit 82 g is disposed on one side (the rear side) of the substrate 82 a in the axial direction. The plurality of electronic components 82 b are disposed on the circuit 82 g.

The motor-side terminal portion 73 b connected to the coil 22 b of the motor part 10 of the connecting bus bar 73 and the substrate-side terminal portion 73 c of the connecting bus bar 73 are disposed at different positions in the axial direction. In the embodiment, as shown in FIG. 4, the substrate-side terminal portion 73 c is disposed on the front side of the motor-side terminal portion 73 b. In the embodiment, the three substrate-side terminal portions 73 c are linearly disposed in the X axis direction.

The through hole portion 82 f connected to the connecting bus bar 73 is provided on the other side (the front side) of the substrate 82 a in the axial direction. In the embodiment, the through hole portion 82 f is a through hole. The substrate-side terminal portion 73 c of the connecting bus bar 73 is connected to the substrate 82 a via the through hole portion 82 f. In the embodiment, the substrate-side terminal portion 73 c is inserted into the through hole portion 82 f and connected via a solder.

The substrate-side terminal portion 73 c of the connecting bus bar 73 has the bent portion 73 d which is bent in a direction intersecting a direction in which the connecting bus bar 73 extends from the motor-side terminal portion 73 b toward the substrate 82 a. In the embodiment, the bent portion 73 d extends to the rear side. A front side end of the bent portion 73 d is connected to the substrate-side terminal portion 73 c which is bent and extends toward the substrate 82 a. The substrate-side terminal portion 73 c passes through the through hole portion 82 f of the substrate 82 a and is connected to the substrate 82 a via a solder.

The motor part 10 and the substrate 82 a are electrically connected via the plurality of connecting bus bars 73. In the embodiment, the motor part 10 and the substrate 82 a are electrically connected via the three connecting bus bars 73. A plurality of through hole portions 82 f which connects the substrate-side terminal portions 73 c of the plurality of connecting bus bars 73 are provided on the other side (the front side) of the substrate 82 a in the axial direction. In the embodiment, three through hole portions 82 f are provided in the substrate. The plurality of through hole portions 82 f are disposed linearly. In the embodiment, the three through hole portions 82 f are disposed in the X axis direction at a predetermined interval. The interval between the through hole portions 82 f is the same as an interval between the three connecting bus bars 73.

As shown in FIG. 4, the motor part 10 has a motor-side connection terminal 22 g which connects the coil 22 b to the other end in the axial direction. In the embodiment, the motor-side connection terminal 22 g is disposed at a front side end of the bus bar assembly 30, has a flat portion 22 g 1 in the Y axis direction, and faces the front side. A threaded portion (not shown) into which a bolt 25 is screwed is provided on the flat portion 22 g 1.

FIG. 5 is a side view of the connecting bus bar assembly 75. A substrate side end of the connecting assembly main body portion 75 a of the connecting bus bar assembly 75 is connected to the substrate 82 a, as shown in FIG. 5. In the embodiment, a protruding portion 75 b which is elastically deformable and has a stepped portion on a tip end side thereof is provided at the substrate side end of the connecting assembly main body portion 75 a. The protruding portion 75 b protrudes from the substrate side end of the connecting assembly main body portion 75 a toward the substrate 82 a. A hole portion (not shown) having a smaller diameter than an outer diameter of the stepped portion is provided in the substrate 82 a. Therefore, when the protruding portion 75 b is inserted into the hole portion and the stepped portion is contracted and passes through the hole portion, the stepped portion returns to an original size thereof, and the protruding portion 75 b does not come out of the hole portion. Therefore, the connecting bus bar assembly 75 can be fixed to the substrate 82 a. The method of fixing the connecting bus bar assembly 75 to the substrate 82 a is not limited to the method using the protruding portion 75 b. The connecting bus bar assembly 75 may be fastened and fixed to the substrate 82 a with screws or the like.

(Substrate Cover 61)

As shown in FIGS. 1 and 3, a substrate cover 61 is disposed in an opening of the substrate accommodating portion 84 and closes the opening of the substrate accommodating portion 84. The substrate cover 61 is disposed parallel to the substrate 82 a. Therefore, the electric oil pump 1 can be downsized in a direction (the Y direction) orthogonal to the axial direction. The substrate cover 61 has a plurality of fixing portions 85 fixed to the case 50. In the embodiment, the fixing portions 85 are bolts.

The electric oil pump 1 is mounted on a lower surface of a transmission (not shown). The electric oil pump 1 is accommodated in an oil pan provided below the transmission. The electric oil pump 1 suctions oil in the oil pan from the inlet and discharges it from the outlet.

(Radiation Fin 86)

As shown in FIG. 2, the case 50 has a plurality of radiation fins 86 which extend radially outward from the outer surface of the cylindrical portion 13 d of the motor housing 13 and extend in a direction intersecting the axial direction. In the embodiment, the radiation fins 86 protrude in the X axis direction and extend in the Y axis direction on both +X side and −X side of the outer surface of the cylindrical portion 13 d of the motor housing 13. The plurality of radiation fins 86 are disposed at intervals in the axial direction. Heat from the substrate 82 a and the motor part 10 can be dissipated by these radiation fins 86.

(Support Portion 77)

Further, as shown in FIG. 1, a support portion 77 which connects a pair of radiation fins 86 adjacent to each other in the axial direction is provided between the pair of radiation fins 86. An inter-fin through hole 78 passing therethrough in the X axis direction is provided in the support portion 77. The inter-fin through hole 78 allows oil stored between the radiation fins 86 to flow when the electric oil pump 1 is disposed in the oil pan.

The radiation fins 86 and the support portion 77 are provided between the cylindrical portion 13 d and the substrate 82 a. Therefore, the heat generated from the substrate 82 a and the connecting bus bar 73 can be dissipated via the radiation fins 86 and the support portion 77. Further, the heat can be further dissipated by the oil flowing through the inter-fin through hole 78 provided in the support portion 77.

<Operation and Effect of Electric Oil Pump 1>

Next, the operation and effect of the electric oil pump 1 will be described. As shown in FIG. 1, when the motor part 10 of the electric oil pump 1 is driven, the shaft 11 of the motor part rotates, and the outer rotor 47 b also rotates as the inner rotor 47 a of the pump rotor 47 rotates. When the pump rotor 47 rotates, the oil suctioned from the inlet of the pump part 40 moves through the accommodating portion 60 of the pump part 40 and is discharged from the outlet.

(1) Here, in the electric oil pump 1 according to the embodiment, as shown in FIG. 4, the connecting bus bar assembly 75 is disposed between the cylindrical portion 13 d of the motor part 10 and the substrate 82 a. Therefore, the connecting bus bar assembly 75 can be disposed compactly in the electric oil pump 1 as compared with a case in which the connecting bus bar assembly 75 is disposed at a position other than between the cylindrical portion 13 d and the substrate 82 a. Thus, the electric oil pump 1 can be downsized.

(2) Further, the connecting bus bar assembly 75 passes through the hole portion 50 b extending between the other side of the cylindrical portion 13 d in the axial direction and the substrate 82 a. Therefore, since the connecting bus bar assembly 75 is disposed in the hole portion 50 b of the case 50, the connecting bus bar assembly 75 can be easily disposed with respect to the case 50.

(3) Further, the connecting bus bar assembly 75 has the connecting bus bar 73 and the connecting assembly main body portion 75 a, and the connecting bus bar 73 and the connecting assembly main body portion 75 a are an integrally molded product formed of a resin. Therefore, the insulation between the plurality of connecting bus bars 73 and between the connecting bus bars 73 and the case 50 can be improved, and positioning accuracy of the connecting bus bars 73 with respect to the connecting bus bar assembly 75 can be improved.

(4) Further, the connecting bus bar assembly 75 extends from the coil 22 b toward the substrate 82 a in a direction orthogonal to the central axis J of the shaft 11. Therefore, a length of the connecting bus bar assembly 75 can be shortened, and it is possible to suppress the size of the electric oil pump 1 in an extending direction of the connecting bus bar assembly 75.

(5) Further, the connecting bus bar 73 is connected to the end of the substrate 82 a on the other side in the axial direction, and the circuit 82 g is disposed on one side of the substrate 82 a in the axial direction. Therefore, it is possible to cause the connecting bus bar 73 and the circuit 82 g to be spaced apart from each other. Thus, the influence of noise and heat generated from the connecting bus bar 73 on the circuit can be suppressed.

(6) Further, the motor-side terminal portion 73 b of the connecting bus bar 73 and the substrate-side terminal portion 73 c of the connecting bus bar 73 are disposed at different positions in the axial direction. Therefore, a degree of freedom of the position at which the substrate-side terminal portion 73 c of the connecting bus bar 73 is connected to the substrate 82 a can be increased according to a type, a size, or the like of the substrate 82 a.

(7) Further, the motor-side terminal portion 73 b of the connecting bus bar 73 is in contact with the motor-side connection terminal 22 g, and the bolt 25 is passed therethrough to be connected to the motor-side connection terminal 22 g. Therefore, in a state in which the motor-side terminal portion 73 b of the connecting bus bar 73 is in contact with the motor-side connection terminal 22 g, the motor-side terminal portion 73 b can be easily connected to the motor-side connection terminal 22 g.

(8) Further, the substrate-side terminal portion 73 c of the connecting bus bar 73 passes through the through hole portion 82 f of the substrate 82 a and is connected to the substrate 82 a. Therefore, it is possible to facilitate workability of an operation in which the substrate-side terminal portion 73 c of the connecting bus bar 73 is connected to the substrate 82 a.

(9) Further, the substrate-side terminal portion 73 c of the connecting bus bar 73 has the bent portion 73 d, the substrate-side terminal portion 73 c is connected to the substrate-side end of the bent portion 73 d, and the substrate-side terminal portion 73 c passes through the through hole portion 82 f and is connected to the substrate 82 a via the solder. When the connecting bus bar 73 contracts in the extending direction, the bent portion 73 d is bent. Therefore, expansion and contraction of the connecting bus bar 73 can be absorbed by the bent portion 73 d. Thus, stress concentration acting on the solder which connects the substrate 82 a with the substrate-side terminal portion 73 c can be suppressed.

(10) Further, the plurality of through hole portions 82 f are disposed linearly. Therefore, it is possible to facilitate workability of an operation in which of the substrate-side terminal portions 73 c of the connecting bus bars 73 inserted in the plurality of through hole portions 82 f are soldered.

(11) Further, the substrate-side end of the connecting assembly main body portion 75 a of the connecting bus bar assembly 75 passes through the hole portion 50 b and is connected to the substrate 82 a. Therefore, the substrate-side end of the connecting bus bar assembly 75 can be fixed to the substrate 82 a.

(12) In addition, the length of the substrate 82 a in the axial direction is shorter than the length of the assembly 45 in the axial direction, and the substrate 82 a is disposed within the axial range of the assembly 45. Therefore, an increase in the length of the electric oil pump 1 in the axial direction is suppressed, and miniaturization can be realized.

Although the exemplary embodiments of the disclosure have been described above, the disclosure is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof. These embodiments and variations thereof are included in the scope and gist of the disclosure and, at the same time, are included in the disclosure described in the claims and the equivalent scope thereof. 

What is claimed is:
 1. An electric oil pump comprising: a motor part having a shaft disposed along a central axis extending in an axial direction; a pump part located on one side of the motor part in the axial direction and driven by the motor part via the shaft to discharge oil; and a control part which controls an operation of the motor part, wherein the motor part includes a rotor fixed to the other side of the shaft in the axial direction, a stator disposed to face the rotor, and a motor housing having a cylindrical portion which accommodates the rotor and the stator, the pump part includes a pump rotor mounted on the shaft which protrudes from the motor part to one side in the axial direction and a pump housing having an accommodating portion which accommodates the pump rotor, the control part includes a plurality of electronic components and a substrate having a surface on which the plurality of electronic components are mounted, the surface of the substrate is disposed radially outward from the cylindrical portion of the motor housing to face the motor housing and extends in the axial direction, the stator has a coil, the coil and the substrate are electrically connected via a connecting bus bar assembly, and the connecting bus bar assembly is disposed between the cylindrical portion of the motor part and the substrate.
 2. The electric oil pump according to claim 1, wherein: the motor housing has a case which extends from an outer surface of the cylindrical portion in a direction orthogonal to the axial direction, the case has a hole portion which extends between the other side of the cylindrical portion in the axial direction and the substrate, and the connecting bus bar assembly passes through the hole portion.
 3. The electric oil pump according to claim 2, wherein: the connecting bus bar assembly includes a connecting bus bar connected to the coil, and a connecting assembly main body portion in which the connecting bus bar is disposed, and the connecting bus bar and the connecting assembly main body portion are an integrally molded product formed of a resin.
 4. The electric oil pump according to claim 3, wherein the connecting bus bar assembly extends from the coil toward the substrate in a direction orthogonal to the central axis of the shaft.
 5. The electric oil pump according to claim 3, wherein: a substrate-side terminal portion of the connecting bus bar is connected to an end of the substrate on the other side in the axial direction, and a circuit is disposed on one side of the substrate in the axial direction.
 6. The electric oil pump according to claim 3, wherein a motor-side terminal portion connected to the coil of the motor part of the connecting bus bar and a substrate-side terminal portion of the connecting bus bar are disposed at different positions in the axial direction.
 7. The electric oil pump according to claim 6, wherein: the motor part has a motor-side connection terminal which connects the coil on the other side in the axial direction, and the motor-side terminal portion of the connecting bus bar is in contact with the motor-side connection terminal, and a bolt passes therethrough and is connected thereto.
 8. The electric oil pump according to claim 6, wherein: a through hole portion connected to the connecting bus bar is provided on the other side of the substrate in the axial direction, and the substrate-side terminal portion of the connecting bus bar passes through the through hole portion and is connected to the substrate.
 9. The electric oil pump according to claim 8, wherein: the substrate-side terminal portion of the connecting bus bar has a bent portion which is bent in a direction intersecting a direction in which the connecting bus bar extends from the motor-side terminal portion toward the substrate, the substrate-side terminal portion is connected to a substrate-side end of the bent portion, and the substrate-side terminal portion passes through the through hole portion of the substrate and is connected to the substrate via a solder.
 10. The electric oil pump according to claim 8, wherein: the motor part and the substrate are electrically connected via a plurality of connecting bus bars, a plurality of through hole portions which connect the respective substrate-side terminal portions of the plurality of connecting bus bars are provided on the other side of the substrate in the axial direction, and the plurality of through hole portions are disposed linearly.
 11. The electric oil pump according to claim 3, wherein: the case has a substrate accommodating portion which is located radially outside of the cylindrical portion and extends in the axial direction to accommodate the substrate, the substrate accommodating portion has a placing surface portion which faces the cylindrical portion and on which the substrate is placed, the hole portion is open in the placing surface portion, and a substrate-side end of the connecting assembly main body portion of the connecting bus bar assembly passes through the hole portion and is connected to the substrate.
 12. The electric oil pump according to claim 1, wherein the substrate has an axial length shorter than an axial length of an assembly formed by combining the motor part and the pump part and is disposed within an axial range of the assembly. 